Merge pull request #1914 from hashicorp/vault

Add Vault image

library/vault

@@ -0,0 +1,4 @@
+# maintainer: Jeff Mitchell <[email protected]> (@jefferai)
+
+v0.6.0: git://github.com/hashicorp/docker-vault@a77fd5f7256af73c082cfef56403ecc4df58fa94 0.6
+latest: git://github.com/hashicorp/docker-vault@a77fd5f7256af73c082cfef56403ecc4df58fa94 0.6